949 resultados para Area in hectare
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The aim of this study is to assess the frequency of rabies antibodies in free-ranging capuchin monkeys (Cebus apella nigritus) in a fragmented, environmentally protected, rural area of southeastern Brazil. Thirty-six free-ranging monkeys were tested by the rapid fluorescent focus inhibition test for detection of antibodies against rabies virus. Four individuals (11.11 %) had neutralizing antibody titers a parts per thousand yen0.25 IU/mL, demonstrating rabies virus exposure.
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We investigated the effects of injection into the supraoptic nucleus (SON) of losartanand PD 123319 (nonpeptide AT(1) and AT(2)- angiotensin II [ANG II] receptor antagonists, respectively); d(CH2)(5)-Tyr(Me)-AVP (AVPA; an arginine-vasopressin [AVP] V-1 receptor antagonist), FK 409 (a nitric oxide [NO] donor), and N-W-mtro-(L)-arginine methyl ester ((L)-NAME; an NO synthase inhibitor) oil water intake, sodium chloride 3% (NaCl) intake and arterial blood pressure induced by injection of ANG 11 into the lateral septal area (LSA). Mate Holtzman rats (250-300 g) were implanted with cannulae into SON and LSA unilaterally. The drugs were injected in 0.5 mul over 30-60 s. Controls were injected with a similar volume of 0.15 M NaCl. ANG II was injected at a dose of 10 pmol. ANG II antagonists and AVPA were injected at doses of 80 nmol. FK 409 and (L)-NAME were injected at doses of 20 and 40 mug, respectively. Water and NaCl intake was measured over a 2-h period. Prior administration of losartan into the SON decreased water and NaCl intake induced by injection of ANG II. While there was a decrease in water intake, ANG II-induced NaCl intake was significantly increased following injection of AVPA. FK 409 injection decreased water intake and sodium intake induced by ANG II. L-NAME alone increased water and sodium intake and induced a pressor effect. (L)-NAME-potentiated water and sodium intake induced by ANG II. PD 123319 produced no changes in water or sodium intake induced by ANG II. The prior administration of losartan or AVPA decreased mean arterial pressure (MAP) induced by ANG II. PD 123319 decreased the pressor effect of ANG II to a lesser degree than losartan. FK 409 decreased the pressor effect of ANG II while (L)-NAME potentiated it. These results suggest that both ANG II AT, and AVP V, receptors and NO within the SON may be involved in water intake, NaCl intake and the pressor response were induced by activation of ANG II receptors within the LSA. These results do not support the involvement of LSA AT(2) receptors in the mediation of water and NaCl intake responses induced by ANG II, but influence the pressor response. (C) 2004 Elsevier B.V. All rights reserved.
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The circumventricular structures and the lateral hypothalamus (LH) have been shown to be important for the central action of angiotensin II (ANGII) on water and electrolyte regulation. Several anatomical findings have demonstrated neural connection between circumventricular structures and the LH, the present experiments were conducted to investigate the role of the alpha-adrenergic antagonists and agonistic injected into the LH on the water intake, sodium and potassium excretion elicited by injections of ANGII into the lateral ventricle (LV), the water intake was measured every 30 min over a period of 120 min. The sodium, potassium and urinary volume were measured over a period of 120 min in water-loaded rats. The injection of ANGII into the LV increased the water intake, which was reduced by previous injection of clonidine (an alpha-2-adrenergic agonist) into the LH. The injection of yohimbine (an alpha-2-adrenergic antagonist) and prazosin (an alpha-l-adrenergic antagonist) into the LH, which was done before injecting ANGII into the LV, also reduced the water intake induced by ANGII. The injection of ANGII into the LV reduced the sodium, potassium and urinary volume. Previous treatment with clonidine attenuated the action of ANGII in reducing the sodium, potassium and urinary volume, whereas previous treatment with yohimbine attenuated the effects of ANGII but with less intensity than that caused by clonidine. Previous treatment with prazosin increased the inhibitory effects of ANGII in those parameters. The injection of yohimbine and prazosin, which was done before the injection of clonidine, attenuated the effect of clonidine on the ANGII mechanism. The results of this study led us to postulate that when alpha-2-adrenergic receptors are blocked, the clonidine may act on the imidazoline receptors to produce its effects on the ANGII mechanism. We may also conclude that the LH is involved with circumventricular structures, which present excitatory and inhibitory mechanisms. Such mechanisms are responsible for regulating the renal excretion of sodium, potassium and water, (C) 2000 Elsevier B.V.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Introduction. Brain arginine(8)-vasopressin (AVP), through the V-1a- and V-2-receptors, is essential for the maintenance of mean arterial pressure (MAP). Central AVP interacts with the components of the renin-angiotensin system, which participate in MAP regulation. This study all to determine the effects of V-1a-, V-2- and V-1a/V-2-AVP selective antagonists and AT(1)- and AT(2)-angiotensin II (Ang II) selective antagonists on the MAP induced by AVP injected into the medial septal area (MSA) of the brain.Materials and methods. Male Holtzman rats with stainless steel cannulae implanted into the MSA were used in experiments. Direct MAP was recorded in Conscious rats.Results. AVP administration into the MSA caused a prompt and potent pressor response in a dose-dependent fashion. Pretreatment with the V-1a- and V-2-antagonists reduced, whereas prior injection of the V-1a/V-2-antagonist induced a decrease in the MAP that remained below the baseline. Both AT(1)- and AT(2)-antagonists elicited a decrease, While simultaneous injections of two antagonists were more effective in decreasing the MAP induced AVP.Conclusion. These results indicate there is a synergism bell the V-1a- and V-2-AVP, and AT(1)- AT, and AT(2)-Ang II receptors in the MSA in the regulation of MAP.
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Os tubarões enfrentam muitos obstáculos para sobreviver nos primeiros anos de vida e muitas espécies ocupam áreas de berçário. Embora estimativas de sobrevivência, particularmente para jovens, sejam essenciais para acessar, monitorar e manejar efetivamente populações animais, existem poucos cálculos destas estimativas para populações de tubarões e poucas estimativas baseadas em métodos diretos para estes animais em suas áreas de berçário. Métodos de marcação e recaptura foram utilizados no presente estudo para estimar o tamanho populacional e a sobrevivência de jovens tubarões-limão (Negaprion brevirostris) em uma área de berçário na Reserva Biológica do Atol das Rocas, Brasil. Os indivíduos foram amostrados entre 1999 e 2003 e as estimativas de tamanho populacional variaram entre 12 a 100 indivíduos jovens e a taxa de sobrevivência entre 24 e 54%, com média de 44,6% durante o período de amostragem mais robusto. A população destes tubarões jovens diminuiu ao longo de nosso estudo, ainda que as taxas de sobrevivência tenham aumentado durante o mesmo período. Mesmo um nível moderado de pesca e a remoção de fêmeas maduras em áreas adjacentes podem afetar dramaticamente pequenas populações de tubarões num berçário pequeno e isolado como o Atol das Rocas. As taxas de sobrevivência e tamanho populacional relativamente mais baixos em Rocas podem ser resultado das diferenças nas características físicas deste berçário, comparadas a outros utilizados pela espécie no Atlântico norte-ocidental. Tais parâmetros comparativamente mais baixos no Atol das Rocas sugerem a fragilidade da população jovem de tubarões-limão neste berçário.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Seventy specimens of Hypsiboas albopunctatus (Anura: Hylidae) were collected and surveyed for endoparasites in Brasilia, Brazil at the end of the rainy season (February and March) in 2005. Sixteen males (22.86%) were infected by Rhabdias sp., Aplectana sp., Cosmocerca sp., and Falcaustra mascula. Rhabdias sp., a lung parasite, presented the highest prevalence (8.57%), mean intensity of infestation (1.333), and mean abundance (0.114). Moreover, this is the first report of a rhabdiasid nematode in the Hylidae in Brazil. The intestinal parasites, Cosmocerca sp. and Aplectana sp., had a similar prevalence (5.71%), but the former presented a higher mean intensity of infestation and mean abundance. The behavior and food habits of amphibians are responsible for the differences in their helminthofauna, and this study presents four new records of nematodes in H. albopunctatus.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Maieta guianensis Aubl. and M. poeppigii Mart. ex. Triana (Melastomataceae) are among the most common myrmecophytic plants in the Amazonian forest understory. These myrmecophytes are colonized exclusively by the ants Pheidole minutula Mayr or Crematogaster sp. and usually host two other arthropods, the spider Faiditus subflavus Exline and Levi and the recently described stilt bug Jalysus ossesae Henry. In this study, the association between J ossesae and the myrmecophytic plants M. guianensis and M. poeppigii in an upland forest area in central Amazon, Brazil, is described. The presence of the stilt bugs on M. guianensis and M. poeppigii and on plants around these myrmecophytes was recorded in five transects. The number and position of the stilt bugs on the leaf surface (upper or lower) and leaf type (with or without domatia) of these myrmecophytes, as well as their behavioral acts, were recorded. Jalysus ossesae was found only on the myrmecophytic plants M. guianensis and M. poeppigii. The stilt bug occurred at similar frequencies on M. guianensis and M. poeppigii, and the number of leaves significantly influenced the presence and number of stilt bugs on these myrmecophytes. Feeding, agonistic interaction between males, and mating were observed. Our data indicate that J. ossesae uses the myrmecophytes M. guinanensis and M. poeppigii as reproductive and foraging sites.
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Análise espectral de flores utilizada por aves nectarívoras em áreas urbanas. O objetivo deste trabalho foi estabelecer a característica espectral das flores produtoras de néctar visitadas por nectarívoros em áreas urbanas. Este estudo foi desenvolvido na região central do município de Taubaté, no nordeste do Estado de São Paulo. As áreas amostradas incluíram espaços verdes, tais como praças e parques e a vegetação das ruas e avenidas. Foram registradas 12 espécies de plantas utilizadas por cinco espécies de aves nectarívoras. As espécies de flores mais visitadas foram aquelas que refletiram em comprimento de onda longos (>600 nm). Foi discutida a capacidade de detecção das aves em função de visão tetracromática das aves nectarívoras e da conspicuidade das flores em ambientes urbanos. Finalmente, foi abordado o problema da escassez de plantas atrativas para aves nectarívoras nas áreas verdes urbanas e a necessidade de se aumentar a quantidade dessas espécies de plantas para incrementar a biodiversidade em regiões urbanas.
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Foram estudadas a composição e diversidade de abelhas em uma área agrícola no município de Rio Claro, Estado de São Paulo, de maio de 2003 a junho de 2004, utilizando armadilha de Moericke. O local de coleta, uma área com 58,08 hectares, caracteriza-se pela produção de grãos e a prática de plantio direto, sendo que 70% da área de entorno é utilizada para o plantio de cana-de-açúcar. Foram coletadas 456 abelhas distribuídas em 20 gêneros, pertencentes às famílias Andrenidae (4,8%), Apidae (40,8%) e Halictidae (54,4%). Espécimes dos gêneros Dialictus (38%) e Diadasia (30%) foram predominantes nesta área. A diversidade de espécies avaliadas pelos índices de Shannon e Simpson foram H =1,88 e 1/D= 4.15, respectivamente, e o índice de Equitatibilidade de 0,61.